The armies of heaven were following the Lord. These may be angelic beings, but 17:14 refers to his faithful followers being with Him, and the fine linen reference is similar to 19:8.
A sharp sword was coming out of His mouth, and with this He will rule the nation. Then there is a quote of Psalm 2:9. Again, we should remember the powerful side of the character of Jesus. He is the Lord Almighty. Then to emphasise the point we are told He will tread the winepress of the fury of God's wrath. Let me remind you again that wrath has two essential parts to it: (i) it is a passionate hatred of sin; (ii) it is completely rational and just. The use of the word fury here emphasises the passionate side. To see wrath purely as a cold logical outworking or morality is to miss a vital part of it. We do not realise the true horror of sin and its effects.
Then we get another name "King of Kings, Lord of Lords" (cf 17:14).
Verses 18 and 19 seem rather gruesome to us. The reference to birds of the air eating up the flesh points to the utter and complete defeat of the world, rather than being some scene from a horror movie. Note that this applies to all. We often talk about the gospel being for all, rich and poor, great and small, and so it is. But judgement is also for all. All who do not repent will suffer the wrath of God, rich and poor, great and small. Sometimes we speak as if the poor or the weak are somehow more righteous than the rest of the people, this is not true at all.
Finally the beast gathers his armies to fight against the "rider on the horse". There is no talk of a battle, just of his defeat. The beast and false prophet were then thrown into the lake of fire.